Protesters fill Cairo's Tahrir Square after former Egyptian President Hosni Mubarak is sentenced to 25 years in prison. NBC's Richard Engel reports.

By NBC News, msnbc.com staff and news services

Updated at 7:20 p.m. ET: CAIRO - Egypt's ousted ruler Hosni Mubarak was sentenced to life in prison Saturday for complicity in the killings of protesters who eventually overthrew him. He could have received the death penalty.

Presiding judge Ahmed Refaat also sentenced his former interior minister, Habib el-Adli, to life in prison on the same charge. But Mubarak's two sons -- Gamal and Alaa -- were acquitted on corruption charges.

The mixed ruling set off street protests and by nightfall, a large crowd of up to 10,000 was back in Cairo's Tahrir Square, the birthplace of the uprising, to vent anger over the acquittals. Similar protesters were held in other cities, including the Mediterranean port city of Alexandria and Suez on the Red Sea.

On Sunday morning, dozens of young Egyptians stormed into the campaign headquarters of presidential candidate Ahmed Shafiq for the Fayoum area south of Cairo on Sunday, the state's Al-Ahram news website reported.

All the headquarters contents including furniture and computer devices were destroyed, Al-Ahram online said. It was the second attack on Shafiq's headquarters in few days.

Shafiq was the last prime minister of deposed president Hosni Mubarak and his success in getting through to a second round of Egypt's presidential election has angered opponents who see him as a symbol of a regime that they took to the streets to oust in mass protests.

Shafiq on Saturday said Mubarak's sentence proved no one was above the law.

"Those rulings certainly disprove any claims that a presidential candidate can reproduce a ruling system that has ended," he said, responding to critics who say Shafiq would revive the old order.

Protesters disagreed.

"Justice was not served," said Ramadan Ahmed, whose son was killed on Jan. 28, the bloodiest day of last year's uprising. "This is a sham," he said outside the courthouse.

Protesters chanted: "A farce a farce, this trial is a farce" and "The people want execution of the murderer."

NBC News, citing state TV, said Mubarak was taken to Tora prison after the court hearing. Egypt TV quoted unidentified medical sources as saying Mubarak had suffered a health crisis as he arrived at the prison and was being treated in the helicopter that transported him and then in the prison hospital.

Asmaa Waguih / Reuters

Pictures of people who died during last year's revolution are seen in front of security forces next to the courthouse in Cairo where former president Hosni Mubarak will heard the verdict in his trial Saturday.

Judge: 30 years of tyrannyThe judge said the uprising ended 30 years of tyranny, saying the people who protested against poverty and oppression were peaceful, according to the newspaper.

Mubarak, 84, was acquitted of the graft charges he faced. His life sentence -- which in Egypt typically is 25 years but in Mubarak's case really means the rest of his life -- was for failing to prevent the killing of 900 protesters.

Mubarak's ex-security chief, Habib el-Adly, also was convicted of complicity in the killings and received a life sentence.

Violent reactions between both opponents and supporters of Former Egyptian President Hosni Mubarak can be seen after Mubarak was sentenced to life in prison for the killing of protesters.

A statement issued by the Muslim Brotherhood's presidential campaign team called for a retrial.

"The public prosecutor did not carry out its full duty in gathering adequate evidence to convict the accused for killing protesters," said Yasser Ali, official spokesman for the Mohamed Mursi campaign.

Others also expressed discontent.

"Initial, fleeting satisfaction, followed by disappointment, and then anger," said Shadi Hamid, director of research at the Brookings Doha Center and a fellow at the Saban Center for Middle East Policy at the Brookings Institution, in a message on Twitter.

"I'd think this verdict would spur greater consensus between Islamists ... and liberals," he added.

'Filled with anger'Nader Bakkar, the spokesman of Al-Nour Salafist Party, said in a tweet translated by Ahram Online that Egyptians were "filled with anger and disappointment."

But some reacted with joy at the news.

Voters lined up in Cairo to choose from five leading candidates: a socialist, two Islamists, and two with ties to former President Hosni Mubarak. NBC's Richard Engel reports.

Soha Saeed, the wife of one of about 850 people killed in the street revolt that toppled Mubarak on Feb. 11, 2011, shouted: "I'm so happy. I'm so happy."